External sensing device for vehicle, method of correcting axial deviation and recording medium

ABSTRACT

A driving support device has a lane marking recognition unit that recognizes at least two lane markings based on a taken image; a deviation angle calculation unit that calculates a deviation angle based on at least the two lane markings; an obstacle recognition unit that recognizes an obstacle position based on the taken image; a camera deviation angle correction unit that corrects the obstacle position recognized by the obstacle recognition unit by the deviation angle; a radar deviation angle correction unit that corrects the obstacle position detected by a radar by the deviation angle; and a driving support processing unit that executes a driving support process based on the corrected obstacle positions.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims benefit of the filing date of JapanesePatent Application No. 2013-106290 filed on May 20, 2013, the disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an external sensing device for a vehicle whichcorrects a deviation angle between an axial direction of an onboardcamera and an obstacle detection sensor having the same axis to bemounted in a vehicle and a traveling direction of a vehicle, a method ofcorrecting axis deviation thereof and a non-transitory computer readablerecording medium recorded with an executable program for correcting thedeviation angle.

2. Description of the Related Arts

Recently, a vehicle control system such as a following distance warningsystem, a preceding vehicle following control system, collisionavoidance/reduction brake system is becoming widespread. In the vehiclecontrol system, an external sensing device for a vehicle is used fordetecting an object which could be an obstacle. The external sensingdevice for a vehicle has an obstacle detection sensor such as an onboardcamera, a millimeter wave radar and a laser radar.

When the external sensing device for a vehicle has a radar having lowmounting precision and a radar reference axis deviates with respect to atraveling direction (the front) of a vehicle, the obstacle cannot bedetected correctly. Adjusting the radar reference axis to the travelingdirection of the vehicle based on the object (for example, a pole besidea road) detected by the radar has been proposed in JP4665903B.

SUMMARY OF THE INVENTION

In the related art disclosed above, a problem in which axis deviation ofthe radar reference axis cannot be corrected properly remains asexplained below.

As illustrated in FIG. 7, when a vehicle 90 is moving straight, theradar detects an object A such that the object A comes close to thevehicle 90 in an opposite direction of the traveling direction of thevehicle 90 (arrow in solid line). On the other hand, when the radarreference axis is deviated, the radar often detects the object A suchthat the object A comes close to the vehicle 90 from an obliquedirection (arrow in broken line). However, the object detected by theradar often includes an error in a lateral direction due to ambientenvironment or a shape of the target obstacle (arrow in long and shortdashed line). Therefore, the related art described above cannotcalculate a deviation angle of the radar reference axis correctly andcannot correct the axis deviation precisely.

The invention has been developed to solve the above-described problem,and an object of the invention is to provide an external sensing devicefor a vehicle which corrects a deviation angle precisely, a method ofcorrecting axis deviation thereof and a non-transitory computer readablerecording medium recorded with an executable program for correcting thedeviation angle.

In view of the above-described problems, an external sensing device fora vehicle of a first invention that corrects a deviation angle betweenan axial direction of an onboard camera and an obstacle detection sensormounted in a vehicle to have a same axis and a traveling direction ofthe vehicle has: a lane marking recognition unit that recognizes atleast two lane markings painted on a road based on a taken image inwhich the traveling direction of the vehicle is taken by the onboardcamera; a deviation angle calculation unit that decides whether thevehicle is moving straight, and calculates the deviation angle based onat least the two lane markings recognized by the lane markingrecognition unit when the vehicle is moving straight; and a deviationangle correction unit that corrects an obstacle position recognizedbased on the taken image and an obstacle position detected by theobstacle detection sensor by the deviation angle calculated by thedeviation angle calculation unit.

In the external sensing device for a vehicle of a second invention, theonboard camera and the obstacle detection sensor are accommodated in onecasing and are adjusted so that an optical axis direction of the onboardcamera and an irradiation direction of the obstacle detection sensorhave a same axis.

In the external sensing device for a vehicle of a third invention, thedeviation angle calculation unit determines a positional deviationamount between a vanishing point that is determined based on at leastthe two lane markings recognized by the lane marking recognition unitand a center of the taken image, and calculates the deviation anglebased on the positional deviation amount.

In the external sensing device for a vehicle of a fourth invention, thedeviation angle correction unit decides whether the deviation anglecalculated by the deviation angle calculation unit is equal to or morethan a predetermined threshold value and corrects the obstacle positionwhen the deviation angle is equal to or more than the threshold value.

In the external sensing device for a vehicle of a fifth invention, thedeviation angle calculation unit does not calculate the deviation anglein case that the lane marking recognition unit cannot recognize the lanemarkings or in case that the vehicle is not moving straight.

The external sensing device for a vehicle of a sixth invention furtherhas a driving support processing unit that executes a driving supportprocess for the vehicle based on the obstacle position corrected by thedeviation angle correction unit.

In view of the above-mentioned problems, a recording medium of a seventhinvention is a non-transitory computer readable medium with anexecutable program stored thereon that makes a computer function as theexternal sensing device for a vehicle according to the first invention.

In view of the above-mentioned problems, a method of correcting axialdeviation of an eighth invention having a lane marking recognition unit,a deviation angle calculation unit and a deviation angle correction unitthat corrects a deviation angle between an axial direction of an onboardcamera and an obstacle detection sensor mounted in a vehicle to have asame axis and a traveling direction of the vehicle, includes:recognizing by the lane marking recognition unit at least two lanemarkings painted on a road based on a taken image in which the travelingdirection of the vehicle is taken by the onboard camera; decidingwhether the vehicle is moving straight, and calculating the deviationangle by the deviation angle calculation unit based on at least the twolane markings recognized by the lane marking recognition unit when thevehicle is moving straight; and correcting by the deviation anglecorrection unit an obstacle position recognized based on the taken imageand an obstacle position detected by the obstacle detection sensor bythe deviation angle calculated in the deviation angle calculation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view for explaining an example of an externalsensing device for a vehicle in an embodiment of the invention;

FIG. 2A is an explanatory view for explaining axial deviation of theonboard camera and the radar in FIG. 1 in a state without the axialdeviation, and FIG. 2B is an explanatory view for explaining axialdeviation of the onboard camera and the radar in FIG. 1 in a state withthe axial deviation;

FIG. 3 is a block diagram illustrating a structure of a driving supportdevice according to the embodiment of the invention;

FIG. 4A is an explanatory view of a taken image without the axialdeviation for explaining a specific example of a deviation anglecalculation process in a deviation angle calculation unit in FIG. 1, andFIG. 4B is an explanatory view of a taken image with the axial deviationfor explaining a specific example of the deviation angle calculationprocess in the deviation angle calculation unit in FIG. 1;

FIG. 5 is a flowchart illustrating an operation of the driving supportdevice in FIG. 3;

FIG. 6 is a flowchart illustrating a deviation angle correction processin FIG. 5; and

FIG. 7 is an explanatory view for explaining a problem in the relatedart.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment

A preferred embodiment of the invention will be explained in detail withreference to accompanying drawings as necessary. In the embodiment andeach alternative, a unit having the same function is labeled with thesame number and explanation thereof will be omitted.

External Sensing Device for a Vehicle

Referring to FIGS. 1 to 2B, an example of a sensing device 2 provided ina driving support device (external sensing device for a vehicle) 1 willbe explained.

As illustrated in FIG. 1, in the sensing device 2, a millimeter waveradar 2A (FIG. 2) and an onboard camera 2B are accommodated in a casing2C so as to have the same axis. The sensing device 2 is adjusted suchthat an irradiation direction of the millimeter wave radar 2A and anoptical axis direction of the onboard camera 2B are coaxial. The sameaxis is referred as a sensing axis herein below. The sensing axis isadjusted to coincide with a traveling direction of a vehicle 90 and thesensing device 2 is attached near a rear view mirror 91 of the vehicle90.

The millimeter wave radar 2A corresponds to an obstacle detection sensoraccording to claims.

Originally, as illustrated in FIG. 2A, the sensing device 2 is attachedsuch that a sensing axis α coincides with the traveling direction β ofthe vehicle 90. However, as illustrated in FIG. 2B, the sensing axis αof the sensing device 2 may deviate from the traveling direction β ofthe vehicle 90. In this state, an obstacle position cannot be determinedprecisely and intended driving support control cannot be executed.Therefore, the driving support device 1 needs to correct a deviationangle θ between the sensing axis α and the traveling direction β of thevehicle 90.

As reasons for the deviation of the sensing axis α, variations inadjustment accuracy of the sensing axis α when the sensing device 2 isattached, axial deviation of the sensing axis α associated with acontact of an object on the sensing device 2, and an occurrence of athrust angle of the vehicle 90 can be considered.

Structure of the Driving Support Device

A structure of the driving support device 1 will be explained withreference to FIG. 3.

The driving support device 1 is mounted in the vehicle 90 (FIG. 1) andexecutes a driving support process such as cruise control of the vehicle90 and warning to a driver. The driving support device 1 has the sensingdevice 2 (the millimeter wave radar 2A and the onboard camera 2B), asensor processing unit 3 and a driving support processing unit 4.

In FIG. 3, the millimeter wave radar 2A is illustrated as a “radar 2A”.

Further, in FIG. 3, a warning device 50, a steering control device 60,an acceleration control device 70 and a brake control device 80 areillustrated as structure elements of the vehicle 90 related to thedriving support device 1.

The millimeter wave radar 2A has a transmitting antenna from which amillimeter wave radar is irradiated to an obstacle as a transmittingwave and a receiving antenna which receives the millimeter wavereflected on the obstacle as a receiving wave (not illustrated).Further, the millimeter wave radar 2A generates a beat signal by mixingthe transmitting wave and the receiving wave to output the beat signalto a signal processing unit 30.

Since the millimeter radar 2A is disclosed, for example, inJP2012-26791A (incorporated in the invention by the citation), detailedexplanation will be omitted.

The onboard camera 2B is a CCD (Charge Coupled Device) camera or a CMOS(Complementary Metal Oxide Semiconductor) camera which can take imagesin a visible light region or an infrared region. The onboard camera 2Boutputs the taken image in the traveling direction (a front direction)of the vehicle 90 to an image processing unit 31.

The sensor processing unit 3 determines the obstacle position based onvarious signals from the sensing device 2, calculates the deviationangle θ between the sensing axis α and the traveling direction β of thevehicle 90, and corrects the obstacle position by the determineddeviation angle θ. The sensor processing unit 3 has the signalprocessing unit 30, the image processing unit 31, a deviation anglecalculation unit 32, a radar deviation angle correction unit 33, acamera deviation angle correction unit 34 and an obstacle decision unit35.

The signal processing unit 30 detects the obstacle position (distanceand direction) based on the beat signal input from the millimeter waveradar 2A. The signal processing unit 30 has a distance calculation unit301 and a direction calculation unit 303.

The distance calculation unit 301 calculates a distance from the vehicle90 to the obstacle. For example, the distance calculation unit 301analyses a frequency of the beat signal by FFT (Fast Fourier Transform)and detects a peak on a frequency axis. When a relative speed differencebetween the vehicle 90 and the obstacle exists, a frequency of thereceiving wave shifts due to the Doppler effect. Therefore, the distancecalculation unit 301 can calculate the obstacle position.

The direction calculation unit 303 calculates an obstacle direction tothe vehicle 90. In case that the obstacle positions in front of thevehicle 90, phases of respective beat frequencies match, and thereby atransition frequency among beat signals becomes zero. On the other hand,in case that the obstacle positions obliquely with respect to thevehicle 90, a phase difference based on a path difference from thetransmitting antenna to the receiving antenna is generated and atransition frequency corresponding to the phase difference appears amongthe beat signals. Therefore, the direction calculation unit 303 measuresthe transition frequency and can determine the obstacle direction basedon the transition frequency.

The direction calculation unit 303 may be input with a correctioncommand signal which indicates to correct the obstacle position by thedeviation angle θ from the radar deviation angle correction unit 33described later. In this case, the direction calculation unit 303corrects the obstacle direction according to the deviation angle θindicated by the correction command signal. For example, the directioncalculation unit 303 refers to a direction correction amount table inwhich the deviation angle θ is associated with a direction correctionamount of the obstacle, and corrects the obstacle direction by thedirection correction amount according to the deviation angle θ.

The direction correction amount table is set, for example, manually orautomatically in a production line.

The signal processing unit 30 generates obstacle data which indicatesthe obstacle position and outputs the obstacle data to the obstacledecision unit 35.

The image processing unit 31 recognizes lane markings and the obstacleposition based on the taken image input from the onboard camera 2B. Theimage processing unit 31 has a lane marking recognition unit 311 and anobstacle recognition unit 313.

The lane marking recognition unit 311 recognizes two lane markingspainted on a road in the taken image. For example, the lane markingrecognition unit 311 executes a pattern matching with a vanishing pointdirection pattern and an edge as a lane marking recognition process anddetermines positions of the lane markings based on the taken image.

Since the lane marking recognition process is disclosed in JP2012-89005A(incorporated in the invention by the citation), explanation thereofwill be omitted.

The obstacle recognition unit 313 recognizes the obstacle position inthe traveling direction of the vehicle 90 based on the taken image. Forexample, the obstacle recognition unit 313 executes an obstaclerecognition process such as an edge region extraction process and acolor region extraction process on the taken image and determines theobstacle position (a coordinate) of the obstacle in the taken image.

When the correction command signal is input from the camera deviationangle correction unit 34 described later, the obstacle recognition unit313 corrects the obstacle position according to the deviation angle θindicated by the correction command signal. For example, the obstaclerecognition unit 313 refers to a coordinate correction amount table inwhich the deviation angle θ is associated with a coordinate correctionamount in the taken image and corrects the obstacle position by acoordinate change amount according to the deviation angle θ.

The coordinate correction amount table is, for example, set manually orautomatically in the production line.

Further, the obstacle recognition unit 313 calculates a distance fromthe vehicle 90 to the obstacle by applying the motion stereo method totwo taken images taken at different times.

Since the motion stereo method is disclosed, for example, inJP2012-52884A (incorporated in the invention by the citation), detailedexplanation thereof will be omitted.

The image processing unit 31 generates image processing data indicatinga position and a distance of the obstacle in the taken image andpositions of lane markings, and outputs the image processing data to theobstacle decision unit 35. Farther, the image processing unit 31 outputsthe image processing data and the taken image to the deviation anglecalculation unit 32.

The deviation angle calculation unit 32 calculates a positionaldeviation amount between the vanishing point and a center of the takenimage. The vanishing point is determined from at least the two lanemarkings included in the image processing data. The taken image is inputfrom the image processing unit 31. Further, the deviation anglecalculation unit 32 calculates the deviation angle θ based on thepositional deviation amount.

The deviation angle calculation unit 32 decides whether the vehicle 90is moving straight based on a lane marking shape, a steering angle or anangular velocity of the vehicle 90.

For example, the deviation angle calculation unit 32 executes a firstapproximation process on lane markings included in the taken image anddetermines whether the lane marking shape is straight. In case that thelane marking shape is determined as straight, the deviation anglecalculation unit 32 decides that the vehicle 90 is moving straight. Onthe other hand, in case that the lane marking shape is not determined asstraight, the deviation angle calculation unit 32 decides that thevehicle 90 is not moving straight.

The deviation angle calculation unit 32 may obtain the steering anglefrom the steering control device 60 to determine whether the vehicle 90is moving straight.

Further, the deviation angle calculation unit 32 may obtain the angularvelocity of the vehicle 90 from an angular velocity sensor (notillustrated) provided in the vehicle 90 to determine whether the vehicle90 is moving straight.

Next, the deviation angle calculation unit 32 decides whether the lanemarking recognition unit 311 can recognize at least the two lanemarkings from the taken image. Shortly, the deviation angle calculationunit 32 determines whether at least two valid lane markings are includedin the image processing data.

In case that the vehicle is moving straight and at least the two lanemarkings can be recognized, the deviation angle calculation unit 32preferably calculates the deviation angle θ and outputs the deviationangle θ to the radar deviation angle correction unit 33 and the cameradeviation angle correction unit 34. While, in case that the vehicle isnot moving straight or at least the two lane markings cannot berecognized, the deviation angle calculation unit 32 preferably does notcalculate the deviation angle θ. Thus, a situation can be avoided, inwhich the obstacle position is corrected by the deviation anglecalculation unit 32 even when the deviation angle θ is not calculatedprecisely.

Specific Example of the Deviation Angle Calculation Process

Referring to FIGS. 4A and 4B, a specific example of the deviation anglecalculation process by the deviation angle calculation unit 32 will beexplained (see FIGS. 2A to 3 as needed).

The specific example illustrates a process in which the deviation angleis calculated based on the vanishing point determined from two lanemarkings 92R, 92L. As illustrated in FIGS. 4A and 4B, the deviationangle calculation unit 32 determines an intersection to which the twolane markings 92R, 92L extend respectively as the vanishing point M.Further, the deviation angle calculation unit 32 determines anintermediate line L which passes the vanishing point M and is parallelwith a vertical axis of the taken image. Then, the deviation anglecalculation unit 32 determines the positional deviation amount Δ (notillustrated in FIG. 4A) between an intermediate coordinate C on ahorizontal axis of the taken image and an intermediate line L.

In case that the sensing axis α and the traveling direction β of thevehicle 90 coincide as illustrated in FIG. 2A, the intermediatecoordinate C and the intermediate line L coincide as illustrated in FIG.4A. Therefore, the positional deviation amount Δ becomes zero. On theother hand, in case that the sensing axis α deviates from the travelingdirection β of the vehicle 90 as illustrated in FIG. 2B, theintermediate coordinate C and the intermediate line L do not coincide asillustrated in FIG. 4B. The greater the deviation angle θ becomes, thegreater the positional deviation amount Δ becomes.

Accordingly, the deviation angle calculation unit 32 calculates thedeviation angle θ from the positional deviation amount Δ. For example,the deviation angle calculation unit 32 refers to a deviation angleconversion table in which the positional deviation amount Δ isassociated with the deviation angle θ, and converts the positionaldeviation amount Δ to the deviation angle θ.

The deviation angle conversion table is set, for example, manually orautomatically in the production line in consideration of a view angle ofthe onboard camera 2B.

Returning to FIG. 3, the structure of the driving support device 1 willbe explained continuously.

The radar deviation angle correction unit 33 makes the signal processingunit 30 correct the obstacle position by the deviation angle θ inputfrom the deviation angle calculation unit 32. Shortly, the radardeviation angle correction unit 33 generates a correction command signalincluding the deviation angle θ to output the correction command signalto the signal processing unit 30.

At this time, the radar deviation angle correction unit 33 preferablydecides whether the deviation angle θ is equal to or more than apredetermined threshold value Th. In case that the deviation angle θ isequal to or more than the threshold value Th, the radar deviation anglecorrection unit 33 outputs the correction command signal to the signalprocessing unit 30. On the other hand, in case that the deviation angleθ is less than the threshold value Th, the radar deviation anglecorrection unit 33 does not output the correction command signal to thesignal processing unit 30. Thus, the radar deviation angle correctionunit 33 does not make the signal processing unit 30 correct the obstacleposition in case of little influence of the axis deviation, and therebyhunting of the obstacle position can be prevented.

The threshold value Th is set manually or automatically in theproduction line.

The camera deviation angle correction unit 34 makes the image processingunit 31 correct the obstacle position by the deviation angle θ inputfrom the deviation angle calculation unit 32. Shortly, the cameradeviation angle correction unit 34 generates the correction commandsignal including the deviation angle θ and outputs the correctioncommand signal to the image processing unit 31.

At this time, the camera deviation angle correction unit 34 preferablydecides whether the deviation angle θ is equal to or more than thethreshold value Th. In case that the deviation angle θ is equal to ormore than the threshold value Th, the camera deviation angle correctionunit 34 outputs the correction command signal to the image processingunit 31. On the other hand, in case that the deviation angle θ is lessthan the threshold value Th, the camera deviation angle correction unit34 does not output the correction command signal to the image processingunit 31. Thus, the camera deviation angle correction unit 34 does notmake the image processing unit 31 correct the obstacle position in caseof little influence of the axis deviation, and thereby the hunting ofthe obstacle position can be prevented.

The radar deviation angle correction unit 33 and the camera deviationangle correction unit 34 correspond to a deviation angle correction unitin claims.

Further, since the radar deviation angle correction unit 33 and thecamera deviation angle correction unit 34 use the same threshold valueTh, decision results whether the deviation angle θ is equal to or morethan the threshold value Th become the same.

The obstacle decision unit 35 integrates the obstacle data input fromthe signal processing unit 30 with the image processing data input fromthe image processing unit 31. Further, the obstacle decision unit 35decides whether the obstacle recognized by the onboard camera 2B and theobstacle detected by the radar 2A are the same.

In case that a distance between the obstacles included in the imageprocessing data and the obstacle data is less than a predetermineddistance threshold value, the obstacle decision unit 35 decides thatboth the obstacles are the same. On the other hand, in case that adistance between the obstacles included in the image processing data andthe obstacle data is equal to or more than the predetermined distancethreshold value, the obstacle decision unit 35 decides that both theobstacles are different. Then, the obstacle decision unit 35 generatesobstacle position information which indicates each obstacle position.

The obstacle decision unit 35 outputs the generated obstacle positioninformation to the driving support processing unit 4.

The driving support processing unit 4 executes the driving supportprocess based on the obstacle position information input from theobstacle decision unit 35. The driving support processing unit 4 has afollowing distance warning unit 40, a preceding vehicle followingprocess unit 41, a collision reduction brake processing unit 42 and acollision avoidance processing unit 43.

When a following distance between the vehicle 90 and a preceding vehicle(obstacle) is short, the following distance warning unit 40 warns to adriver. For example, in case that the following distance between thevehicle 90 and the preceding vehicle is short, the following distancewarning unit 40 commands the warning device 50 to warn the driver.

The preceding vehicle following process unit 41 makes the vehicle 90follow a preceding vehicle. For example, the preceding vehicle followingprocess unit 41 commands the steering control device 60, theacceleration control device 70 and the brake control device 80 that thevehicle 90 follows the preceding vehicle having a proper followingdistance.

The collision reduction brake processing unit 42 reduces impact when thevehicle 90 collides with an obstacle. For example, in case that there isa possibility for the vehicle 90 to collide with the obstacle, thecollision reduction brake processing unit 42 commands the brake controldevice 80 to slow down the vehicle 90.

The collision avoidance processing unit 43 avoids collision with theobstacle. For example, in case that there is a possibility for thevehicle 90 to collide with the obstacle, the collision avoidanceprocessing unit 43 commands the steering control device 60 such that thevehicle 90 is steered to avoid the obstacle.

It is needless to say that, in addition to the obstacle positioninformation, the driving support processing unit 4 can use drivingcondition information which indicates a driving condition of the vehicle90 when the driving support process is executed. For example, thedriving support processing unit 4 obtains detection results from a speedsensor, a raindrop sensor (weather sensor) and an inclination sensor(not illustrated) as the driving condition information and uses thedetection results for cruise control of the vehicle 90 and a warning tothe driver. Further, for example, the driving support processing unit 4obtains road condition information which indicates a road condition asthe driving condition information by road-to-vehicle communication anduses the road condition information for the driving support process.

The warning device 50 warns the driver based on a command input from thedriving support processing unit 4. For example, the warning device 50executes the following warnings (A) to (D) in predetermined combinationsand makes the driver recognize a possibility of the collision.

-   (A) Tightening a seat belt with predetermined tension-   (B) Vibrating a steering wheel-   (C) Blinking a warning lamp-   (D) Outputting a warning sound to a speaker

The steering control device 60 controls a steering actuator (notillustrated) based on the command input from the driving supportprocessing unit 4. For example, the steering control device 60 controlsa steering operation of the steering actuator such that the vehicle 90follows the preceding vehicle or the vehicle 90 avoids the obstacle.

The acceleration control device 70 controls an accelerator (notillustrated) based on the command input from the driving supportprocessing unit 4. For example, the acceleration control device 70controls an opening/closing of the accelerator (throttle) such that thevehicle 90 follows the preceding vehicle.

The brake control device 80 controls a brake actuator (not illustrated)based on the command input from the driving support processing unit 4.For example, in case that there is a possibility that the vehicle 90collides with the obstacle, the brake control device 80 controls adeceleration operation of the brake actuator such that the vehicle 90decelerates.

Since the driving support process is disclosed, for example, inJP2007-91208A (incorporated in the invention by the citation), detaileddescription thereof will be omitted.

Operation of the Driving Support Device

Referring to FIG. 5, an operation of the driving support device 1 willbe explained (see FIG. 3 as needed).

The driving support device 1 generates the taken image of the travelingdirection of the vehicle 90 taken by the onboard camera 2B. Then, thedriving support device 1 recognizes the obstacle position in thetraveling direction of the vehicle 90 based on the taken image by theobstacle recognition unit 313 (step S1).

The driving support device 1 irradiates millimeter wave radar(transmitting wave) to the obstacle by the millimeter wave radar 2A andreceives the receiving wave of the millimeter wave radar reflected bythe obstacle. The driving support device 1 generates the beat signal inwhich the transmitting wave and the receiving wave are mixed. Thedriving support device 1 detects the obstacle position based on the beatsignal by the signal processing unit 30 (step S2).

The driving support device 1 corrects the deviation angle θ between thesensing axis α and the traveling direction β of the vehicle 90 (step S3:deviation angle correction process). The deviation angle correctionprocess will be described later in detail (see FIG. 6).

The driving support device 1 decides whether the obstacle recognized bythe onboard camera 2B and the obstacle detected by the radar 2A are thesame by the obstacle decision unit 35, and generates the obstacleposition information (step S4).

The driving support device 1 executes the cruise control of the vehicle90 and the warning to the driver based on the obstacle positioninformation by the driving support processing unit 4 (step S5: drivingsupport process).

Deviation Angle Correction Process

Referring to FIG. 6, the deviation angle correction process illustratedin FIG. 5 will be explained (see FIG. 3 as needed).

The driving support device 1 recognizes at least the two lane markingspainted on the road based on the taken image by the lane markingrecognition unit 311 (step S31: lane marking recognition step).

The driving support device 1 decides whether the vehicle 90 is movingstraight by the deviation angle calculation unit 32 (step S32).

In case that the vehicle 90 is moving straight (Yes in step S32), thedriving support device 1 decides whether at least the two lane markingscan be recognized in step S31 by the deviation angle calculation unit 32(step S33).

In case that at least the two lane markings can be recognized (Yes instep S33), the driving support device 1 calculates the deviation angle θusing the method of the specific example described above by thedeviation angle calculation unit 32 (step S34: deviation anglecalculation step).

The driving support device 1 decide whether the deviation angle θ isequal to or more than the threshold value Th by the radar deviationangle correction unit 33 and the camera deviation angle correction unit34 (step S35).

In case that the deviation angle θ is equal to or more than thethreshold value Th (Yes in step S35), the driving support device 1executes a process of step S36. In this case, the driving support device1 does not correct the deviation angle θ and executes the drivingsupport process.

The driving support device 1 generates the correction command signal bythe camera deviation angle correction unit 34. Then, the driving supportdevice 1 corrects the obstacle position according to the deviation angleθ indicated by the correction command signal by the obstacle recognitionunit 313 (step S36).

The driving support device 1 generates the correction command signal bythe radar deviation angle correction unit 33. Then, the driving supportdevice 1 corrects the obstacle direction according to the deviationangle θ indicated by the correction command signal by the directioncalculation unit 303 (step S37).

The steps S36 and S37 correspond to a deviation angle correction stepdescribed in claims.

The driving support device 1 terminates the deviation angle correctionprocess when the vehicle 90 is not moving straight (No in step S32),when at least the two lane markings cannot be recognized (No in stepS33), when the deviation angle θ is not equal to or more than thethreshold value Th (No in step S35), or when the process in step S37 isdone.

Effect/Advantage

As described above, since at least the two lane markings recognizedbased on the taken image do not suffer lateral deviation, the drivingsupport device 1 can calculate the deviation angle correctly and cancorrect the axis deviation precisely. Thus, the driving support device 1can reduce a burden for an adjusting operation and can realize a properdriving support process.

According to the inventions, the following excellent effects can beacquired.

According to the first, the seventh and the eighth inventions, since atleast the two lane markings recognized based on the taken image do notsuffer the lateral deviation, the deviation angle can be calculatedcorrectly and the axis deviation can be corrected precisely. With theeffect, the first, the seventh and the eighth inventions can reduce aburden for an adjusting operation of the external sensing device for avehicle and can contribute to realize a proper driving support process.

In the second invention, since the axial directions of the onboardcamera and the obstacle detection sensor have been adjusted, theexternal sensing device for a vehicle can be attached in the vehicleeasily.

In the third invention, since the positional deviation amount iscalculated precisely based on the vanishing point and the center in thetaken image, the deviation angle can be calculated correctly.

In the fourth invention, since the obstacle position is not correctedwhen an effect of the axis deviation is less, a situation in which theobstacle position varies frequently can be prevented (huntingprevention). This leads to a contribution to realize a proper drivingsupport process.

In the fifth invention, a situation in which the obstacle position iscorrected even when the deviation angle is not calculated correctly isavoided. This leads to a contribution to realize a proper drivingsupport process.

In the sixth invention, a driving support process based on a correctobstacle position can be executed.

Modification

The invention is not limited to the embodiment described above and cancover various modifications without departing from the object of theinvention. Specific modifications of the invention will be explainedbelow.

In the embodiment, the sensing device 2 has the millimeter wave radar 2Aand the onboard camera 2B, but the invention is not limited thereto.

The sensing device 2 may have a laser radar instead of the millimeterwave radar 2A.

Further, the sensing device 2 may have a second onboard camera (notillustrated) instead of the millimeter wave radar 2A. In this case, thedriving support device 1 has a pair of onboard cameras (stereo camera)and recognizes the obstacle position based on the principle oftriangulation.

The driving support device 1 can execute the deviation angle correctionprocess at an arbitrary timing.

For example, the driving support device 1 can execute the deviationangle correction process at one of the timings (1) to (3) describedbelow.

-   (1) When the sensing device 2 is attached in the vehicle 90 in the    production line-   (2) When the vehicle 90 is maintained in a maintenance shop-   (3) When the driver commands

Especially, in case that the driving support device 1 executes thedeviation angle correction process at the timing of (1), an adjustmentoperation for mating the sensing axis with the traveling direction ofthe vehicle 90 can be omitted when the sensing device 2 is attached inthe vehicle 90. This contributes to a production process reduction.

In the embodiment described above, the driving support device 1 isexplained as an independent hardware, but the invention is not limitedthereto. For example, the driving support device 1 can be executed by anaxis deviation correction program which makes hardware resources such asa CPU, a memory, a hard disk in a computer operate in cooperation as thesensor processing unit 3 and the driving support processing unit 4. Theprogram may be distributed via a communication line or may bedistributed as a recording medium such as a CD-ROM or a flash memory.

What is claimed is:
 1. An external sensing device for a vehicle thatcorrects a deviation angle between an axial direction of an onboardcamera and an obstacle detection sensor mounted in a vehicle to have asame axis and a traveling direction of the vehicle, comprising: a lanemarking recognition unit that recognizes at least two lane markingspainted on a road based on a taken image in which the travelingdirection of the vehicle is taken by the onboard camera; a deviationangle calculation unit that decides whether the vehicle is movingstraight, and calculates the deviation angle based on at least the twolane markings recognized by the lane marking recognition unit when thevehicle is moving straight; and a deviation angle correction unit thatcorrects an obstacle position recognized based on the taken image and anobstacle position detected by the obstacle detection sensor by thedeviation angle calculated by the deviation angle calculation unit. 2.The external sensing device for a vehicle according to claim 1, whereinthe onboard camera and the obstacle detection sensor are accommodated inone casing and are adjusted so that an optical axis direction of theonboard camera and an irradiation direction of the obstacle detectionsensor have a same axis.
 3. The external sensing device for a vehicleaccording to claim 1, wherein the deviation angle calculation unitdetermines a positional deviation amount between a vanishing point thatis determined based on at least the two lane markings recognized by thelane marking recognition unit and a center of the taken image, andcalculates the deviation angle based on the positional deviation amount.4. The external sensing device for a vehicle according to claim 2,wherein the deviation angle calculation unit determines a positionaldeviation amount between a vanishing point that is determined based onat least the two lane markings recognized by the lane markingrecognition unit and a center of the taken image, and calculates thedeviation angle based on the positional deviation amount.
 5. Theexternal sensing device for a vehicle according to claim 1, wherein thedeviation angle correction unit decides whether the deviation anglecalculated by the deviation angle calculation unit is equal to or morethan a predetermined threshold value and corrects the obstacle positionwhen the deviation angle is equal to or more than the threshold value.6. The external sensing device for a vehicle according to claim 2,wherein the deviation angle correction unit decides whether thedeviation angle calculated by the deviation angle calculation unit isequal to or more than a predetermined threshold value and corrects theobstacle position when the deviation angle is equal to or more than thethreshold value.
 7. The external sensing device for a vehicle accordingto claim 3, wherein the deviation angle correction unit decides whetherthe deviation angle calculated by the deviation angle calculation unitis equal to or more than a predetermined threshold value and correctsthe obstacle position when the deviation angle is equal to or more thanthe threshold value.
 8. The external sensing device for a vehicleaccording to claim 1, wherein the deviation angle calculation unit doesnot calculate the deviation angle in case that the lane markingrecognition unit cannot recognize the lane markings or in case that thevehicle is not moving straight.
 9. The external sensing device for avehicle according to claim 2, wherein the deviation angle calculationunit does not calculate the deviation angle in case that the lanemarking recognition unit cannot recognize the lane markings or is casethat the vehicle is not moving straight.
 10. The external sensing devicefor a vehicle according to claim 3, wherein the deviation anglecalculation unit does not calculate the deviation angle in case that thelane marking recognition unit cannot recognize the lane markings or incase that the vehicle is not moving straight.
 11. The external sensingdevice for a vehicle according to claim 4, wherein the deviation anglecalculation unit does not calculate the deviation angle in case that thelane marking recognition unit cannot recognize the lane markings or iscase that the vehicle is not moving straight.
 12. The external sensingdevice for a vehicle according to claim 1 further comprising a drivingsupport processing unit that executes a driving support process for thevehicle based on the obstacle position corrected by the deviation anglecorrection unit.
 13. The external sensing device for a vehicle accordingto claim 2 further comprising a driving support processing unit thatexecutes a driving support process for the vehicle based on the obstacleposition corrected by the deviation angle correction unit.
 14. Theexternal sensing device for a vehicle according to claim 3 furthercomprising a driving support processing unit that executes a drivingsupport process for the vehicle based on the obstacle position correctedby the deviation angle correction unit.
 15. The external sensing devicefor a vehicle according to claim 4 further comprising a driving supportprocessing unit that executes a driving support process for the vehiclebased on the obstacle position corrected by the deviation anglecorrection unit.
 16. The external sensing device for a vehicle accordingto claim 5 further comprising a driving support processing unit thatexecutes a driving support process for the vehicle based on the obstacleposition corrected by the deviation angle correction unit.
 17. Anon-transitory computer readable medium with an executable programstored thereon that makes a computer function as the external sensingdevice for a vehicle according to claim
 1. 18. A method of correctingaxis deviation of an external sensing device for a vehicle having a lanemarking recognition unit, a deviation angle calculation unit and adeviation angle calculation unit that corrects a deviation angle betweenan axial direction of an onboard camera and an obstacle detection sensormounted in a vehicle to have a same axis and a traveling direction ofthe vehicle, comprising steps of: recognizing by the lane markingrecognition unit at least two lane markings painted on a road based on ataken image in which the traveling direction of the vehicle is taken bythe onboard camera; deciding whether the vehicle is moving straight, andcalculating the deviation angle by the deviation angle calculation unitbased on at least the two lane markings recognized by the lane markingrecognition unit when the vehicle is moving straight; and correcting bythe deviation angle correction unit an obstacle position recognizedbased on the taken image and an obstacle position detected by theobstacle detection sensor by the deviation angle calculated in thedeviation angle calculation.